Use of zinc deposited in deciduous teeth as a retrospective measurement of dietary zinc exposure during early development.

Purpose: We proposed that zinc (Zn) deposition in deciduous teeth would be a timed record of exposure to this essential micronutrient over very early life. We tested this hypothesis by gathering information on the maternal and child's diet during pregnancy and early infancy and measuring mineral deposition in the dentine at points during deciduous tooth development. Methods: We developed a short food frequency questionnaire (S-FFQ) to record consumption of food containing Zn during pregnancy and over the first year of life of the child in an Indonesian population. Zn, Sr and Ca were measured by laser ablation ICP-MS in a series of points across the developmental timeline in deciduous teeth extracted from 18 children undergoing the process as part of dental treatment whose mothers completed the SFFQ. Mothers and children were classified into either high Zn or low Zn groups according to calculated daily Zn intake. Results: The Zn/Sr ratio in dentine deposited over late pregnancy and 0-3 months post-partum was higher (p < 0.001, 2-way ANOVA; p < 0.05 by Holm-Sidak post hoc test) in the teeth of children of mothers classified as high Zn consumers (n = 10) than in children of mothers classified as low Zn consumers (n = 8). Conclusion: The S-FFQ was validated internally as adequately accurate to measure zinc intake retrospectively during pregnancy and post-partum (∼7 years prior) by virtue of the correlation with measurements of zinc in deciduous teeth. The ratio of Zn/Sr in deciduous teeth appears to be a biomarker of exposure to zinc nutrition during early development and offers promise for use as a record of prior exposure along a timeline for research studies and, potentially, to identify individuals at heightened risk of detrimental impacts of poor early life zinc nutrition on health in later life and to implement preventative interventions.

Exceptional Concentrations of Gold Nanoparticles in 1,7 Ga Fluid Inclusions From the Kola Superdeep Borehole, Northwest Russia.

In the drill core of the Kola super-deep borehole (SG-3, 12,262 m depth) gold-bearing rocks of Archaean age have been located at depths of 9,500 to 11,000 m. In veins, between 9,052 and 10,744 m, within this gold zone, quartz contains fluid inclusions with gold nanoparticles. There are 4 types of fluid inclusions (1) gas inclusions of dense CO2, (2) liquid-vapor two-phase aqueous inclusions, (3) three-phase inclusions with NaCl daughter crystals, and (4) CO2-aqueous inclusions. In all inclusion types, there are extremely high concentrations of gold. The highest gold concentrations were found in the type 3 and 4 fluid inclusions with an average concentration of c. 750 ppm and may be as high as 6,000 ppm. The presence of gold as nanoparticles in the solutions of these fluid inclusions was determined by optical and spectroscopic methods. We suggest that these fluids could be a precursor of "orogenic gold fluids" which, at the gold concentrations determined, would reduce the requirements for large volumes of metamorphic fluids to form orogenic ore deposits. Further, as nanoparticles, gold could be transported in larger amounts than in true solution.

Radiation therapy port films: a quality assurance study.

PURPOSE: The purpose of this study was to assess the port film acceptance rate in a large community practice setting and to catalog the reasons for rejection. METHODS: Between December 1993 and July 1996, a quality assurance monitor log was maintained on 4,150 patients who underwent a total of 4,450 treatment courses. Port films were taken at the beginning and at the half way point in the treatment course. A total of 20,735 port films were compared with the matching simulation films. We recorded the site being treated, the radiation oncologist who reviewed the films and the reason for rejection. RESULTS: The monthly acceptance rate varied from a low of 67% to a high of 83%, with a gradual upward trend. The single most common reason for rejecting films was a centering problem-12% of all films taken were rejected for this reason. The next most common problems were block placement or body setup errors that caused 3.4% and 2.7% of the films to be rejected, respectively. Average acceptance rates between 10 different sites (abdomen, brain, breast, chest, extremities, head and neck, pelvis, prostate, rectum and spine) varied from 68% to 80%. Individual differences between 12 radiation oncologists reviewing the films varied from 67% to 87%. CONCLUSIONS: A detailed analysis of field localization errors allowed us to identify areas where improvement was needed and suggested that specific guidelines for acceptance would help reduce the variability noted in the acceptance rate between sites and physicians.

Quinpirole inhibits striatal and excites pallidal neurons in freely moving rats.

The activity of single neurons in the striatum of freely moving rats was recorded in response to systemic administration of dopamine agonists selective for either the D1 or D2 family of receptors. At a dose that induced behavioral activation, SKF-38393 (5.0 mg/kg s.c.), a D1 agonist, had no consistent effect on striatal activity, whereas quinpirole (1.0-5.0 mg/kg s.c.), a D2 agonist, inhibited the great majority of striatal neurons. In addition, quinpirole (1.0 mg/kg s.c.) excited neurons of the globus pallidus, which receives an inhibitory projection from the striatum. These results are consistent with models of the basal ganglia in which dopamine, via D2 receptors, inhibits striatopallidal activity, resulting in a disinhibition of neurons in globus pallidus.

The economics of death? A descriptive study of the impact of funeral and cremation costs on U.S. households.

The death-care industry in the United States has been virtually ignored by policy makers. Although the industry is highly fragmented, pricing is becoming increasingly influenced by multinational corporations. This fact coupled with the market structure for services, consumers' preferences, and the attributes of death-care services, has resulted in average funeral cost of over $5,000 per deceased. This figure is over 25 percent higher than the average annual family welfare payment in the United States. As estimated in this paper, the distributional effects of a death occurring within a household varies significantly by income as well as race and ethnicity. The author concludes that Americans should engage more openly in the discussion of death, increase their rate of prearrangements, and seek alternatives to the traditional funeral.

Telomeres, cancer, and aging. Altering the human life span.

Population projections of the aging global society and its fiscal and social impact have depended on assumptions regarding the human life span. Until now, the assumption that the maximum human life span is fixed has been justified. Recent advances in cell biology, genetics, and our understanding of the cellular processes that underlie aging, however, have shown that this assumption is invalid in a number of animal models and suggest that this assumption may become invalid for humans as well. In vitro alteration of telomeres affects cellular senescence, and in vivo manipulation of genes and diet can increase maximum life span in animal models if these discoveries are extended to humans. We may soon be able to extend the maximum human life span and postpone or prevent the onset of diseases associated with aging. Such a possibility requires that we recognize a growing uncertainty in any attempt to project international health care costs into the next few decades. The costs may be significantly lower than projections, if life span increases and age-related disabilities are postponed or less severe, or perhaps higher, if life span increases without altering the onset and severity of disability. An appropriate uncertainty regarding the human life span undermines any attempt to accurately predict health costs in the next century.

Induction of new carbonic anhydrase II following treatment with acetazolamide in DBA and C57 mice.

The mechanism by which animals develop tolerance to the antiepileptic effects of the carbonic anhydrase (CA) inhibitor, acetazolamide, was explored using a quantitative immunocytochemical method. Cerebral cortex sections of DBA/2J mice susceptible to audiogenic seizures and of C57BL/6J nonsusceptible mice were stained with antibody to mouse CA II in controls and following treatment with acetazolamide (40 and 200 mg/kg) for 1, 3, and 5 days. The percentage increases in CA II fluorescent intensity of cells from C57 mice treated with 40 and 200 mg/kg acetazolamide over those of untreated mice were 22 and 36%, respectively, after 1 day, 32 and 40%, respectively, after 3 days, and 17 and 40%, respectively, after 5 days of treatment. The corresponding percentage increases in fluorescent intensity of cells from DBA mice over controls were 13 and 32%, respectively, after 1 day, 17 and 41%, respectively, after 3 days, and 26 and 58%, respectively, after 5 days of treatment. The fluorescent intensity of cells from untreated DBA mice was 35% greater than those of untreated C57 mice. In C57 mice the maximum amount of CA II per cell at each dose occurred 24 h after acetazolamide treatment, whereas the amount in DBA mice continued to increase with time and dose up to 5 days. The differences between the two strains can be explained by changes in distribution of CA II to subcellular locations or by defects in phosphorylation of the molecule.

Uncompensated hospital care: charitable mission or profitable business decision?

Provision of hospital uncompensated care is generally assumed to be adversely affected as increased healthcare competition decreases demand for compensated hospital services. Economic theory, however, suggests the question is more complex. Non-profit hospitals are assumed in this paper to maximize utility as a function of uncompensated care, subject to the constraint that revenues cover costs. For-profit hospitals, in contrast, are assumed to maximize profit while recognizing that failure to meet community expectations regarding provision of uncompensated care could negatively impact profits. Therefore, for-profit hospital supply of uncompensated care focuses on balancing the hospital's marginal costs and marginal benefits. These models predict that non-profit hospitals will respond to increased competition by reducing the supply of uncompensated care. In contrast, for-profit hospitals will increase the supply of uncompensated care when market demand decreases since the concurrent decrease in compensated care reduces the marginal cost of producing uncompensated care. The models also predict that for-profit hospitals will respond to changes in community expectations regarding the provision of uncompensated care.

Phencyclidine-induced increases in striatal neuron firing in behaving rats: reversal by haloperidol and clozapine.

Amphetamine and related drugs of abuse facilitate dopamine transmission in the striatum. This action is believed to underlie the increase in firing of striatal motor-related neurons after amphetamine administration in behaving rats. The present study extended this electrophysiological investigation to phencyclidine (PCP), a nonamphetamine psychomotor stimulant that acts primarily as a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) glutamate receptors. Like amphetamine, PCP (1.0, 2.5, or 5.0 mg/kg) increased the activity of striatal motor-related neurons concomitant with behavioral activation. These effects were blocked by subsequent administration of either 1.0 mg/kg haloperidol or 20.0 mg/kg clozapine, typical and atypical neuroleptics, respectively. Dizocilpine (MK- 801), another noncompetitive NMDA antagonist, mimicked the effect of PCP. Collectively, these results indicate that amphetamine and NMDA antagonists exert comparable effects on striatal motor-related neurons, suggesting that the response of these cells to psychomotor stimulants is regulated by a dopaminergic-glutamatergic influence.